System Design / Roadmap
System Design Interview Roadmap (Phases 1–5)
A battle-tested engineering blueprint covering fundamental mental models, distributed building blocks, 14 classic system designs, and Low-Level Design (LLD) in C# / .NET.
The Universal 9-Step Interview Sequence
Avoid jumping straight to diagrams. Follow this repeatable framework to address ambiguity, calculate constraints, and defend engineering trade-offs systematically.
Requirements Clarification
Separate functional requirements (what it does) from non-functional requirements (scale, latency, availability, durability).
Scale & Capacity Estimation
Estimate Daily Active Users (DAU), Read vs Write ratio, Requests Per Second (RPS), throughput, storage requirements over 5 years.
API Contract Design
Define clean REST or gRPC endpoint contracts with request payloads, query parameters, idempotency headers, and HTTP status codes.
Data Model & Storage Selection
Design schemas, choose relational vs document vs key-value vs time-series, identify primary keys and indexing strategies.
High-Level Architecture
Draw end-to-end components: Clients → DNS/CDN → Load Balancer → API Gateway → Application Services → Cache → Database → Message Queue.
Deep Dive into Critical Components
Zoom into the highest-risk modules: unique ID generation, consistent hashing ring, caching policy, or queue consumer processing.
Bottlenecks & Single Points of Failure
Identify database write limits, memory bounds, hot partitions, network saturation, and SPOF components.
Trade-offs & Justifications
Explain CAP choices (AP vs CP), why Cache-Aside over Write-Through, SQL vs NoSQL, and latency vs consistency trade-offs.
Resilience, Monitoring & Failure Modes
Plan for network partitions, node crashes, circuit breakers, dead-letter queues, telemetry, and health check probes.
Complete 5-Phase Curriculum Breakdown
Master each tier to build confidence across both High-Level Design (HLD) and Low-Level Design (LLD).
Foundations
Fundamental mental models, non-functional requirements, scaling dimensions, and system boundaries.
Core Building Blocks
The essential infrastructure components that power modern distributed web platforms.
Distributed Systems
Tackling the hard realities of distributed coordination, network partitions, and data consistency.
Practical Systems Design
14 classic high-level system design interview scenarios with step-by-step architectural blueprints.
Low-Level Design (LLD) in C# & .NET
Object-oriented principles, design patterns, and clean architecture implementations in modern C#.
How We Study Each Day
For each system design scenario, every day delivers: